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[Twolanerider]

Since finished the new top end work on my old Road Glide have had a couple of the brethren ask about the ACRs that were added.  Since it's come up twice it's probably worth a thread.  It's a simple as one would think; with a couple possible detours.

First off on a bike 2006 or newer and if you've got TTS or some other ECM manager that will let you enable management of the ACRs in the ECM just do it that way.  Or if you've got a good relationship with your dealer have them turn it on for you.  If doing it that way the wiring to make it work is done with a pre-terminated kit you buy from Harley and the physical hook up is an easy chore.

2005 is iffy.  That ECM had more internal memory and some capabilities the 04 and prior units did not.  It was an interim year as HD was getting ready for o2 sensors the next year.  But what it can and can't actually do has always been something of a craps shoot from any documentation I've ever found.  So if your TTS says it can, ok, try it.  If it's quirky, wire the ACRs in off the starter circuit.  That's how mine are and what I've now been asked about a couple times.

Full disclosure here I was concerned about one thing doing it this way and reached out to Jim (HD-Dude) to see if he'd be kind enough to share his experience again.  Of course he did.  And, as always, it was beneficial.

My concern was that directly wiring the ACRs would (obviously) have them on or off.  Nothing in between.  When wired "factory" through the ECM the ACRs pulse.  That's a difference worth noting.  My concern was gaining insight on potential low compression because the ECM won't fire the engine if it senses that compression is too low. 

The work done on my engine has it on the floor at a little over 10.25:1.  That has it in a middle ground of needing ACRs or not.  I didn't have the option of wiring them through the ECM so mine would be hot all the time the engine is turning over (just like manual compression releases would be). So potential low compression with them on was in the back of my mind. 

For anyone doing this don't overthink it.  This isn't a rocket science task. 

You only want the ACRs active while the engine is turning over.  In other words while the starter is engaged.  The wire to the solenoid is only hot then.  There's your power source.  Green wire to the starter solenoid.

The ACRs are not polarized.  It's two wires coming from them and doesn't matter which way they're wired. You might vary a bit but the following is how I did mine.

Behind the battery at the starter relay cut in to the green wire that comes out of the starter relay and goes down to the solenoid.  In a step down heat shrink butt connector I t'd a new wire forward from there then also added an inline fuse that now rests in the dead area to the left of the battery.

On forward of the new inline fuse I added weatherproof toggle switch so I could turn the ACRs on or off as needed (just in case low compression turned out to be an issue).  So inline fuse forward to one side of the switch and out the other side of the switch on forward to the ACRs. 

There is a harness Harley sells to mate to the ACRs.  I used that.  Connected one of it's two wires to the toggle switch and the other to good clean ground in front of the battery.

If I had picked up a trigger at the starter relay using the wire that comes from the handlebar start switch I'd have wired it all up with a relay to take power on downstream to the ACRs.  I didn't want to screw with that and that's why I picked power up on the solenoid or output side of the relay (the bigger green wire) rather than the input or trigger side of the relay.  The output side is ready for the heavier load while the input side may not be.

That's all there is to it though.  No difficulty nor mystery.  I hate hate hate hate hate manual ACRs.  Don't even know why they piss me off but manual compression releases always have.  Despise getting fingers burned.  Was getting heads machined for compression releases anyway so gladly paid the tiny bit extra to get it done for automatic releases rather than manuals.  The ACRs and the accessory harness are surprisingly inexpensive.  By Harley standards they're downright cheap.

Now, having said all this, at least in spring weather so far I'm not sure I needed it.  Would rather be safe than sorry obviously.  So ok with the fact the parts are there.  But with the high torque starter and starting in neutral hot or cold so far the bike has started without using the ACRs.  Conversely just screwing around with it to see how it would behave a couple times it didn't want to start with the ACRs turned on.  So I'm glad I used the toggle switch.

[HD Street Performance]

To add to this already very informative thread
ACRs can be added to most twin cam heads including some aftermarket heads.
I have done them on a few 05s but some of the earlier ECMs were not fully equipped yet, hit or miss.
The factory scheme actually measures cranking rpm and leads the actuation to a target RPM, in other words, pulses them.
After many miles or if the engine is an oil burner the passages will plug up and need to be cleaned. On the bike this can be done but the tank and pipe will need to be pulled to remove the valves.

[Twolanerider]

To add to this already very informative thread
ACRs can be added to most twin cam heads including some aftermarket heads.
I have done them on a few 05s but some of the earlier ECMs were not fully equipped yet, hit or miss.
The factory scheme actually measures cranking rpm and leads the actuation to a target RPM, in other words, pulses them.
After many miles or if the engine is an oil burner the passages will plug up and need to be cleaned. On the bike this can be done but the tank and pipe will need to be pulled to remove the valves.

Eventually having to service the plumbing was something in the back of my head.  I'm old though.  Maybe it'll stay clean on the inside longer than I do !

[porthole]

When I had the cylinders and heads done by John Sachs I had him add the ACR's.
His are a little different.

John installed and I 'automatically' push each plunger before starting 

They work well and is worthwhile to start the bike, especially after a short hot soak such as getting fuel.
Changing the starter to a higher output also helped.

Only problem I  have had is one of the plunger caps fell off some time ago.

[Twolanerider]

When I had the cylinders and heads done by John Sachs I had him add the ACR's.
His are a little different.

John installed and I 'automatically' push each plunger before starting 

They work well and is worthwhile to start the bike, especially after a short hot soak such as getting fuel.
Changing the starter to a higher output also helped.

Only problem I  have had is one of the plunger caps fell off some time ago.

You push the plungers by hand?  So manual releases?  I may be missing a beat here Duane.


Had two things I liked about adding the HD automatic releases.  First was obviously that I didn't have to reach down to push anything on/around the hot engine.  Second is that they are up in the top of the head.  You truly don't see anything.  I despise manual releases so much I don't even want to see them .